Showing posts with label Geology. Show all posts
Showing posts with label Geology. Show all posts

Tuesday, March 03, 2020

Kearsarge



I call it “Kearsarge” and it dominates the view westward through our picture window from my recliner where I’d been spending a lot of time recovering from leg surgery. It wasn’t always called that, however. An old woman who owned a property I managed way back in the 20th century called it “Pequawket Mountain,” and that was the official name for it until 1957, the year it officially became “Kearsarge North.


Why, though? New Hampshire already had a Mount Kearsarge in Merrimack County and what was wrong with “Pequawket Mountain”? That’s what the Pequawket Indians, the local Abenaki branch living in Fryeburg and Conway, called it. It’s one of the most prominent peaks looking west from Fryeburg and Lovell. A trail leading to the top begins in village of Kearsarge which is part of Conway, NH. Perhaps the village people pressured whatever official body decided such things to rename it.


From my property, the mountain is almost due west and its profile is classic. Its southern slope is a long, straight, thirty-degree diagonal leading to the summit after which it drops off with pleasing symmetry to the north for about a third the length of the southern slope. The effect is similar to a wave. As a child, before I ever saw Kearsarge, I drew mountains in almost exactly those relative dimensions. The profile seen from Kezar Lake five miles north of me is similar and I have taken many photographs from both venues. When seen from Fryeburg Village, Kearsarge’s profile is quite different — more a rounded dome than a wave. 

Last October, Kearsarge seemed to bend light at sunset
In early March, the sun sets right behind Kearsarge. I mark seasonal progress by how far north of it the sun descends each evening. By the summer solstice, sunsets will have proceeded northward past Mount Washington to the Baldfaces before turning back southward again until the winter solstice. Often I see stunning displays of light, clouds, colors, and mists too beautiful to describe. Afternoon thunderstorms come in over those mountains too, and my favorite sunsets occur when they break up just as the sun is nearing the horizon. Its rays poke through the mists just before it drops behind again.

Rain squall one evening last summer
Never do I tire of watching all this, and it’s not just the sunsets. Our house is perched on the side of Christian Hill in Lovell which rises to our east. I don’t see rays of sun until after they have first lit up the eastern slopes of Kearsarge and the other mountains. It’s quite stunning after a winter storm during which snow or ice coats every branch of every tree on every mountain. The rising sun lights up each slope — first the very top and then proceeding downward to the base. On such mornings it seems our Creator is in a good mood and wants to show off.

Mount Washington one morning last year
After our house was built on what was then a fully-treed lot, it took me about ten years to open up the view. Each summer I’d cut enough for eight cords to keep the family warm over winter, then I’d twitch each tree up to the landing with an old Ford 8N farm tractor. It was a lot of work, but I saved money on oil, and there was the added benefit of seeing more mountains each succeeding year. I felt like a sculptor, and the more I did, the more our new house felt like home. 

Kearsarge from North Fryeburg corn field last month
When my wife started hinting at downsizing after the kids moved out, I knew I would have a hard time ever selling this place. I’d prefer to die here.


Kearsarge is one of the White Mountains of New Hampshire and Maine, which are relatively young compared to the Green Mountains of Vermont further west. According to prevailing geological opinion, the two ranges were formed by different mountain-building processes. The White Mountains were formed over 100 million years ago as subsurface magma intrusions later exposed by plate tectonics, glaciation, and other erosional processes. The Green Mountains were formed about 400 million years ago when tropical shorelines of an ancient sea were folded upward by continental drift and then also eroded by glaciers.


It’s hard to wrap my mind around such time spans but I keep trying. Four times, glaciers covered those mountains with ice over a mile thick above them, lastly only 20,000 years ago. The earliest humans we know of were in the area only13,000 years ago. Viewed from Lovell, Kearsarge is almost completely tree-covered except for areas recently clearcut. During winter, snow reflects sunlight back to me from those scars and it takes years for newer growth to cover them. They remind me of scars on my head when my mother exposed them using hair clippers to give me a “wiffle” after school let out for summer. By September, those scars were covered too.

Thursday, November 14, 2019

What's Under There?



Remember digging a hole at the beach with your pail and shovel? It’s pretty easy to dig in sand when its grains are held together somewhat by moisture. Dig down far enough though and the hole fills with water. Then its sides collapse and you end up with a shallow depression. Well, that’s something like what we found when replacing a 35-year-old foundation that had been heaving up under a large garage on one of the properties I manage. First, we moved the garage off to the side. Then Colin Micklon and his crew at Micklon Tree and Landscaping dug out the old foundation which had been built on blue clay at the bottom of a hill near Kezar Lake.

Hitting blue clay
Colin got down to an undisturbed level, or “virgin ground,” as it’s called in the trade. Then he set up a pump to suck out accumulating groundwater, trucked away all the fill, and got ready to build a crushed-stone base for the new foundation. Then a nor’easter arrived last month with all that rain. On top of groundwater from several springs in the hillside, it was too much and the blue-clay sides of the hole sloughed back in. While Colin and his crew dealt with that, I consulted my research materials to understand why the blue clay was there.


Whenever I see an excavator or backhoe digging, I pull over and look in the hole. It’s the only way to see what is under the surface, right? That’s basically what geologists do when compiling data on what they call Maine’s “surficial geology.” About fifteen ago I purchased several sets of data from the Maine Geological Survey (MGS) on Lovell and the surrounding area. The MGS arranges its research to correspond with green quadrangle maps from the United States Geological Survey (USGS) you’ve probably seen hanging up in various places.

USGS map Center Lovell Quadrangle
My house is located on the southwest corner of the green map called the “Center Lovell Quadrangle.” Surrounding that are the Fryeburg Quadrangle, the Pleasant Mountain Quadrangle, the North Waterford Quadrangle, and so forth. I purchased those about forty years ago when I first moved to Lovell. I used them in my classroom to teach local geography, to guide me in my deer-hunting expeditions, and to explore cellar holes in abandoned settlements all around the area. The University of New Hampshire has an online collection of USGS Maps going back to the 1890s.


Those maps are great for seeing what is on the surface like old logging roads, jeep trails, elevations, streams, and so forth, but don’t offer any information about what is under the surface. The Maine Geological Survey (MGS) surficial geology maps I purchased were based on data compiled up to 2002, but they’ve since been updated. Teams of state geologists visit each quadrangle periodically and look into whatever excavations are going on at the time, gravel pits, cellar holes, road cuts — wherever they can get peeks underground. They compare visible data with evolving theories about which of at least four ice sheets to have come and gone over this area during the past two million+ years did what.


After purchasing fourteen acres on Lovell’s Christian Hill back in 1980 or so, we began building the house in which we now live. First I cleared the trees, then hired Tommy Barker to dig the cellar hole. (Colin was in kindergarten then.) There’s only a foot or so of topsoil above what’s called “hardpan,” which goes about fifty feet down to bedrock. That, according to the above data, was laid down by a glacier, but which one? Was it the last one that melted back about 11,000 years ago? Or was it one the ice sheets that came and went before it hundreds of thousands of years earlier?


There were no geologists around to consult, but my guess is it was probably all of them. We know the last glacier best and it was estimated to be 1-2 miles thick and very heavy. It had boulders, sand, gravel, and clay contained within it which dropped wherever it melted. Earlier glaciers did the same. They all dropped material which was then compressed by the weight of subsequent glaciers. Maine’s hard pan is like concrete, extremely difficult to break through, and impermeable to water.


That blue clay we encountered near Kezar Lake seems to have been deposited during the last warming period around 11,000 years ago when meltwater was held back by an ice and debris dam and formed a much larger lake geologists call “Lake Pigwacket.” It was many times the size of what’s now Kezar Lake. All this surficial geology overlays bedrock, and it seems that Maine’s bedrock is among the most diverse on the entire planet — but that’s a column for another time.

Sunday, April 08, 2007

Old New England

New England is old, and that’s one of the things I like about it. As most people learned in school, it was one of the first places in North America to be settled by English-speaking people and they left their marks almost everywhere you look. Many of the houses they built are still standing, sometimes with their descendants still living in them. Even where the houses have disintegrated, cellar holes remain.

There’s nothing I like better than to explore the back roads of New England. I keep DeLorme Atlases of four states on the back seat of my car to guide me if I’m lucky enough to find a few hours and indulge my wanderlust. As family obligations or medical treatment force me to drive to Massachusetts several times a year, I try to work in some side trips whenever possible on the way back. I’ve already taken every possible north to south route where the roads are numbered highways, so now I try to plot back-road detours along each of them. As I investigate those, I find many other intriguing, dead-end side roads too. I intend to examine them all before I die.

Usually, I don’t know how long it’s going to take to explore a road, because I don’t always know where it will lead. Many are not in the DeLorme Atlas. If my wife happens to be with me, that may limit how far down a particular road I can go or how many side roads I can take before she loses patience. If I’m traveling alone, I usually get home late. She doesn’t worry so much anymore because she knows what I’m likely to be doing. and the next time we’re passing through the area I’d been exploring, I can show her some the best out-of-the-way places I’ve found.

English-speaking people have lived in the area for over four hundred years and they’ve altered the landscape. In addition to houses and fields, they built stone walls which remain long after the house has fallen in and rotted away, and the fields have grown up to forest again. While driving along, I look for old gnarled maple trees near the road as signs for where an old farmhouse may have been located. Usually, I find a cellar hole nearby.

The earliest evidence of human habitation in northern New England goes back only about nine thousand years. Those people were probably very different from the Abenaki and other tribes encountered by European colonists. They were likely nomadic hunters of big herd animals like mammoths and mastodons, and it’s quite possible they hunted those animals to extinction. Otherwise, they left very little evidence of their stay here. Only careful archaeological investigation produces whatever artifacts they left and those can only be seen in museums or private collections. The next inhabitants, eastern woodland Indians, didn’t leave much behind either. There are some pictographs on a cliff in Lovell, some petroglyphs on rocks in the Penobscot, and some shell middens on the coast, but not much else. Their descendants still live in New England, but they’re largely assimilated, living pretty much the way I do.

Also interesting is evidence of the prehuman geology all around us. Maine, actually, is one of the most geologically varied places on earth. At Border’s recently, I purchased Roadside Geology of Vermont and New Hampshire and I found Roadside Geology of Maine online. It should be arriving in the mail any day now. I’m already trying my wife’s patience when I pull over to examine road cuts along the highway. Especially interesting are the fresh ones, like those exposed during the recent Maine Turnpike widening.

Many of us around here were forced to learn about geology back in 1988 when the US Department of Energy considered trying to bury high-level nuclear waste in the Sebago Batholith. I never heard of a batholith before that, but I read their literature and found out that a huge mass of granite formed under us millions of years ago when some magma tried to break through the earth’s mantle. It couldn’t quite break out into a volcano and cooled underground instead. The DOE said the batholith, or pluton, extended from Westbrook to Lovell and it was seamless - there were no cracks in it. That was surprising news to the dozens of well drillers who had been boring into it for decades and finding lots of cracks. Otherwise they would not have been able to find any water. Lots of angry New Englanders persuaded the Energy Department to look elsewhere for a nuclear waste dump, but my interest in local geology was reignited.

Ever since, it’s taken me a lot longer to get from place to place in New England, because I have to pull over so much and check out the evidence of history.

Published March, 2004